Intensive chemotherapy given in early chronic phase of chronic myelogenous leukemia (CML) has resulted in high numbers of circulating Philadelphia (Ph) chromosome-negative hematopoietic progenitor cells (HPC). We have autografted 30 consecutive patients with CML in chronic phase with HPC collected in this way to facilitate restoration of Ph-negative hematopoiesis in bone marrow after high-dose therapy. Hematopoietic recovery to greater than 0.5 x10(9)/L neutrophils and to greater than 25 x 10(9)/L platelets occurred in all patients, a median of 13 (range, 9 to 32) days and 16 (range, 6 to 106) days postautograft, respectively. Regenerating marrow cells were Ph-negative in 16 (53%) patients and greater than 66% Ph-negative in 10 (33%) patients. Twenty-eight patients are alive 6 to 76 months (median, 24 months) after autografting. Three patients have developed blast crisis from which 2 have died. Eight patients are in complete cytogenetic remission at a median of 20 (range, 6 to 44) months with a median ratio BCR-ABL/ABL of 0.002 (range, <0.001 to 0.01). Eight patients are in major cytogenetic remission at a median of 22 (range, 6 to 48) months. No patient died as a consequence of the treatment. All patients had some degree of stomatitis that was severe in 15 (50%) patients. Gastrointestinal and hepatic toxicities were observed in about one fourth of patients. Thus, autografting with Ph-negative mobilized HPC can result in prolonged restoration of Ph-negative hematopoiesis for some patients with CML; moreover, most autograft recipients report normal or near normal activity levels, suggesting that this procedure need not to be associated either with prolonged convalescence or with chronic debility.